- Release
- Documentation
- Source
- PyPI repo
- Keywords
automotive, car, cars, consumption, engine, engine-map, fitting, fuel, vehicle, vehicles
- Copyright
2014 European Commission (JRC-IET)
- License
Fuefit is a python package that calculates fitted fuel-maps from measured engine data-points based on coefficients with physical meaning.
The Fuefit calculator was developed to apply a statistical fit on measured engine fuel consumption data (engine map). This allows the reduction of the information necessary to describe an engine fuel map from several hundred points to seven statistically calculated parameters, with limited loss of information.
More specifically this software works like that:
- Accepts engine data as input, constituting of triplets of RPM, Power and Fuel-Consumption or equivalent quantities eg mean piston speed (CM), brake mean effective pressure (BMEP) or Torque, fuel mean effective pressure (PMF).
- Fits the provided input to the following formula123:
BMEP = (a + b × CM + c × CM2) × PMF + (a2 + b2 × CM) × PMF2 + loss0 + loss2 × CM2
Recalculates and (optionally) plots engine-maps based on the coefficients that describe the fit:
a, b, c, a2, b2, loss0, loss2
An "execution" or a "run" of a calculation along with the most important pieces of data are depicted in the following diagram:
.----------------------------. .-----------------------------./ Input-Model / / Output(Fitted)-Model /
/----------------------------/ /-----------------------------/
/ +--engine / / +--engine /
/ | +--... / / | +--fc_map_coeffs /
/ +--params / ____________ / +--measured_eng_points /
/ | +--... / | | / | n p fc bmep ... /
/ +--measured_eng_points /==>| Calculator ... ... ... ... /
/ n p fc / / +--fitted_eng_points /
/ -- ---- --- / / | n p fc /
/ 0 0.0 0 / / | ... ... ... /
/ 600 42.5 25 / / +--mesh_eng_points /
/ ... ... ... / / n p fc /
/ / / ... ... ... /
'----------------------------' '-----------------------------'
Apart from various engine-characteristics under /engine the table-columns such as capacity and p_rated, the table under /measured_eng_points must contain at least one column from each of the following categories (column-headers are case-insensitive):
Engine-speed:
N [1/min] N_norm [-] : where N_norm = (N – N_idle) / (N_rated-N_idle) CM [m/sec]Load-Power-capability:
P [kW] P_norm [-] : where P_norm = P/P_MAX T [Nm] BMEP [bar]Fuel-consumption:
FC [g/h] FC_norm [g/KWh] : where FC_norm = FC[g/h] / P_MAX [kW] PMF [bar]
The Input & fitted data-model described above are trees of strings and numbers, assembled with:
- sequences,
- dictionaries,
pandas.DataFrame,pandas.Series.
The program runs on Python-3.3+ and requires numpy/scipy, pandas and win32 libraries along with their native backends to be installed.
On Windows/OS X, it is recommended to use one of the following "scientific" python-distributions, as they already include the native libraries and can install without administrative priviledges:
Assuming you have a working python-environment, open a command-shell (in Windows use cmd.exe BUT ensure python.exe is in its PATH) and try the following console-commands:
- Install
$ pip install fuefit $ fuefit --winmenus ## Adds StartMenu-items, Windows only.
See:
install- Cmd-line
$ fuefit --version 0.0.7-alpha.1 $ fuefit --help ... ## Change-directory into the `fuefit/test/` folder in the *sources*. $ fuefit -I FuelFit_real.csv header+=0 \ -I ./FuelFit.xlsx sheetname+=0 header@=None names:='["p","n","fc"]' \ -I ./engine.csv file_frmt=SERIES model_path=/engine header@=None \ -m /engine/fuel=petrol \ -m /params/plot_maps@=True \ -O full_results_model.json \ -O fit_coeffs.csv model_path=/engine/fc_map_coeffs index?=false \ -O t1.csv model_path=/measured_eng_points index?=false \ -O t2.csv model_path=/mesh_eng_points index?=false \
See:
cmd-line-usage- Excel
$ fuefit --excelrun ## Windows & OS X onlySee:
excel-usage- Python-code
>>> import pandas as pd >>> from fuefit import datamodel, processor, test
>>> inp_model = datamodel.base_model() >>> inp_model.update({...}) ## See "Python Usage" below. # doctest: +SKIP >>> inp_model['engine_points'] = pd.read_csv('measured.csv') ## Pandas can read Excel, matlab, ... # doctest: +SKIP >>> datamodel.set_jsonpointer(inp_model, '/params/plot_maps', True)
>>> datamodel.validade_model(inp_model, additional_properties=False) # doctest: +SKIP
>>> out_model = processor.run(inp_model) # doctest: +SKIP
>>> print(datamodel.resolve_jsonpointer(out_model, '/engine/fc_map_coeffs')) # doctest: +SKIP a 164.110667 b 7051.867419 c 63015.519469 a2 0.121139 b2 -493.301306 loss0 -1637.894603 loss2 -1047463.140758 dtype: float64
See:
python-usage
Tip
The commands beginning with $, above, imply a Unix like operating system with a POSIX shell (Linux, OS X). Although the commands are simple and easy to translate in its Windows counterparts, it would be worthwile to install Cygwin to get the same environment on Windows. If you choose to do that, include also the following packages in the Cygwin's installation wizard:
* git, git-completion
* make, zip, unzip, bzip2
* openssh, curl, wgetBut do not install/rely on cygwin's outdated python environment.
Fuefit- runs on Python-3.3+, and it is distributed on Wheels.
Note
This project depends on the numpy/scipy, pandas and win32 python-packages that themselfs require the use of C and Fortran compilers to build from sources. To avoid this hussle, you can choose instead one of the methods below:
a self-wrapped python distribution like Anaconda/miniconda, Winpython, or Canopy.
Tip
* Under Windows you can try the self-wrapped WinPython distribution, a higly active project, that can even compile native libraries using an installations of Visual Studio, if available (required for instance when upgrading numpy/scipy, pandas or matplotlib with pip).
Just remember to Register your WinPython installation after installation and add your installation into PATH (see faq):
- To register it, go to
Start menu --> All Programs --> WinPython --> WinPython ControlPanel, and thenOptions --> Register Distribution.- For the path, add or modify the registry string-key
[HKEY_CURRENT_USER\Environment] "PATH".
An alternative scientific python-environment is the Anaconda cross-platform distribution (Windows, Linux and OS X), or its lighter-weight alternative, miniconda.
On this environment you will need to install this project's dependencies manually using a combination of
condaandpipcommands. Seerequirements/miniconda.txt, and peek at the example script commands in.travis.yaml.- Check for alternative installation instructions on the various python environments and platforms at the pandas site.
See install for more details
Before installing it, make sure that there are no older versions left over. So run this console-command (using cmd.exe in windows) until you cannot find any project installed:
$ pip uninstall fuefit ## Use `pip3` if both python-2 & 3 are in PATH.You can install the project directly from the PyPi repo_ the "standard" way, by typing the pip in the console:
$ pip install fuefit- If you want to install a pre-release version (the version-string is not plain numbers, but ends with
alpha,beta.2or something else), use additionally--pre. - If you want to upgrade an existing installation along with all its dependencies, add also
--upgrade(or-Uequivalently), but then the build might take some considerable time to finish. Also there is the possibility the upgraded libraries might break existing programs(!) so use it with caution, or from within a virtualenv (isolated Python environment)_. To install an older version issue the console-command:
$ pip install fuefit=1.1.1 ## Use `--pre` if version-string has a build-suffix.- To install it for different Python environments, repeat the procedure using the appropriate
python.exeinterpreter for each environment. Tip
To debug installation problems, you can export a non-empty
DISTUTILS_DEBUGand distutils will print detailed information about what it is doing and/or print the whole command line when an external program (like a C compiler) fails.
After a successful installation, it is important that you check which version is visible in your PATH, so type this console-command:
$ fuefit --version
0.0.7-alpha.1If you download the sources you have more options for installation. There are various methods to get hold of them:
- Download and extract a release-snapshot from github.
- Download and extract a
sdistsource distribution from PyPi repo_. Clone the git-repository at github. Assuming you have a working installation of git you can fetch and install the latest version of the project with the following series of commands:
$ git clone "https://github.com/ankostis/fuefit.git" fuefit.git $ cd fuefit.git $ python setup.py install ## Use `python3` if both python-2 & 3 installed.
When working with sources, you need to have installed all libraries that the project depends on. Particularly for the latest WinPython environments (Windows / OS X) you can install the necessary dependencies with:
$ pip install -r requirements/execution.txt .The previous command installs a "snapshot" of the project as it is found in the sources. If you wish to link the project's sources with your python environment, install the project in development mode:
$ python setup.py developNote
This last command installs any missing dependencies inside the project-folder.
The installation to Anaconda (ie OS X) works without any differences from the pip procedure described so far.
To install it on miniconda environment, you need to install first the project's native dependencies (numpy/scipy), so you need to download the sources (see above). Then open a bash-shell inside them and type the following commands:
$ coda install `cat requirements/miniconda.txt`
$ pip install lmfit ## Workaround lmfit-py#149
$ python setup.py install
$ fuefit --version
0.0.7-alpha.1Attention
Excel-integration requires Python 3 and Windows or OS X!
In Windows and OS X you may utilize the xlwings library to use Excel files for providing input and output to the program.
To create the necessary template-files in your current-directory, type this console-command:
$ fuefit --excelType fuefit --excel {file_path} if you want to specify a different destination path.
In windows/OS X you can type fuefit --excelrun and the files will be created in your home-directory and the Excel will immediately open them.
What the above commands do is to create 2 files:
FuefitExcelRunner{#}.xlsmThe python-enabled excel-file where input and output data are written, as seen in the screenshot below:
After opening it the first tie, enable the macros on the workbook, select the python-code at the left and click the
Run Selection as Pyhonbutton; one sheet per vehicle should be created.The excel-file contains additionally appropriate VBA modules allowing you to invoke Python code present in selected cells with a click of a button, and python-functions declared in the python-script, below, using the mypy namespace.
To add more input-columns, you need to set as column Headers the json-pointers path of the desired model item (see
python-usagebelow,).FuefitExcelRunner{#}.pyPython functions used by the above xls-file for running a batch of experiments.
The particular functions included reads multiple vehicles from the input table with various vehicle characteristics and/or experiment coefficients, and then it adds a new worksheet containing the cycle-run of each vehicle . Of course you can edit it to further fit your needs.
Note
You may reverse the procedure described above and run the python-script instead:
$ python FuefitExcelRunner.pyThe script will open the excel-file, run the experiments and add the new sheets, but in case any errors occur, this time you can debug them, if you had executed the script through LiClipse, or IPython!
Some general notes regarding the python-code from excel-cells:
- An elaborate syntax to reference excel cells, rows, columns or tables from python code, and to read them as
pandas.DataFrameis utilized by the Excel . Read its syntax at~fuefit.excel.FuefitExcelRunner.resolve_excel_ref. - On each invocation, the predefined VBA module pandalon executes a dynamically generated python-script file in the same folder where the excel-file resides, which, among others, imports the "sister" python-script file. You can read & modify the sister python-script to import libraries such as 'numpy' and 'pandas', or pre-define utility python functions.
- The name of the sister python-script is automatically calculated from the name of the Excel-file, and it must be valid as a python module-name. Therefore:
- Do not use non-alphanumeric characters such as spaces( ), dashes(-) and dots(.) on the Excel-file.
- If you rename the excel-file, rename also the python-file, or add this python
import <old_py_file> as mypy`
- On errors, a log-file is written in the same folder where the excel-file resides, for as long as the message-box is visible, and it is deleted automatically after you click 'ok'!
- Read http://docs.xlwings.org/quickstart.html
Example command:
fuefit -v\
-I fuefit/test/FuelFit.xlsx sheetname+=0 header@=None names:='["p","rpm","fc"]' \
-I fuefit/test/engine.csv file_frmt=SERIES model_path=/engine header@=None \
-m /engine/fuel=petrol \
-O ~t2.csv model_path=/fitted_eng_points index?=false \
-O ~t2.csv model_path=/mesh_eng_points index?=false \
-O ~t.csv model_path= -m /params/plot_maps@=TrueThe most powerful way to interact with the project is through a python REPL (Read-Eval-Print Loop). So fire-up a python or ipython shell and first try to import the project just to check its version:
>>> import fuefit
>>> fuefit.__version__ ## Check version once more. '0.0.7-alpha.1'
>>> fuefit.__file__ ## To check where it was installed. # doctest: +SKIP /usr/local/lib/site-package/fuefit-...
If the version was as expected, take the base-model and extend it with your engine-data (strings and numbers):
>>> from fuefit import datamodel, processor
>>> inp_model = datamodel.base_model()
>>> inp_model.update({
... "engine": {
... "fuel": "diesel",
... "p_max": 95,
... "n_idle": 850,
... "n_rated": 6500,
... "stroke": 94.2,
... "capacity": 2000,
... "bore": None, ##You do not have to include these,
... "cylinders": None, ## they are just for displaying some more engine properties.
... }
... })
>>> import pandas as pd
>>> df = pd.read_excel('fuefit/test/FuelFit.xlsx', 0, header=None, names=["n","p","fc"])
>>> inp_model['measured_eng_points'] = dfFor information on the accepted model-data, check both its JSON-schema at ~fuefit.datamodel.model_schema, and the ~fuefit.datamodel.base_model:
Next you have to validate it against its JSON-schema:
>>> datamodel.validate_model(inp_model, additional_properties=False)If validation is successful, you may then feed this model-tree to the fuefit.processor, to get back the results:
>>> out_model = processor.run(inp_model)
>>> print(datamodel.resolve_jsonpointer(out_model, '/engine/fc_map_coeffs'))
a 164.110667
b 7051.867419
c 63015.519469
a2 0.121139
b2 -493.301306
loss0 -1637.894603
loss2 -1047463.140758
dtype: float64
>>> print(out_model['fitted_eng_points'].shape)
(262, 11)Hint
You can always check the sample code at the Test-cases and in the cmdline tool fuefit.__main__.
The 'lmfit' fitting library can be parameterized by setting/modifying various input-model properties under /params/fitting/.
In particular under /params/fitting/coeffs/ you can set a dictionary of coefficient-name --> lmfit.parameters.Parameter such as min/max/value, as defined by the lmfit library (check the default props under fuefit.datamodel.base_model() and the example columns in the ExcelRunner).
This project is hosted in github. To provide feedback about bugs and errors or questions and requests for enhancements, use github's Issue-tracker.
To get involved with development, you need a POSIX environment to fully build it (Linux, OSX, or Cygwin on Windows).
Liclipse IDE
Within the sources there are two sample files for the comprehensive LiClipse IDE:
eclipse.projecteclipse.pydevproject
Remove the eclipse prefix, (but leave the dot(.)) and import it as "existing project" from Eclipse's File menu.
Another issue is due to the fact that LiClipse contains its own implementation of Git, EGit, which badly interacts with unix symbolic-links, such as the docs/docs, and it detects working-directory changes even after a fresh checkout. To workaround this, Right-click on the above file Properties --> Team --> Advanced --> Assume Unchanged
- Kostis Anagnostopoulos (software design & implementation)
- Georgios Fontaras (methodology inception, engineering support & validation)
- Stefanos Tsiakmakis
- Biagio Ciuffo
Authors would like to thank experts of the SGS group for providing useful feedback.
Bastiaan Zuurendonk, Maarten Steinbuch(2005): "Advanced Fuel Consumption and Emission Modeling using Willans line scaling techniques for engines", Technische Universiteit Eindhoven, 2005, Department Mechanical Engineering, Dynamics and Control Technology Group, http://alexandria.tue.nl/repository/books/612441.pdf↩
Yuan Zou, Dong-ge Li, and Xiao-song Hu (2012): "Optimal Sizing and Control Strategy Design for Heavy Hybrid Electric Truck", Mathematical Problems in Engineering Volume 2012, Article ID 404073, 15 pages doi:10.1155/2012/404073↩
Xi Wei (2004): "Modeling and control of a hybrid electric drivetrain for optimum fuel economy, performance and driveability", Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University↩